java.lang.ClassCastException: $Proxy0

spring练习中出现:
Exception in thread "main" java.lang.ClassCastException: $Proxy0
	at test.spring.test.MainTest.main(MainTest.java:12)

解决方法就是用接口来接受获得的bean

package test.spring.test;

import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;

import test.spring.service.UserService;
import test.spring.service.impl.UserServiceImpl;

public class MainTest {
	public static void main(String[] args) throws Exception {
		XmlBeanFactory factory = new XmlBeanFactory(new ClassPathResource("beans.xml"));
		UserService userService = (UserService)factory.getBean("service");
		userService.createUser("roundzheng", "123");
		userService.createUser("dsfds", "fdsfsd");
		userService.getPassword("roundzheng");
		if(userService.readUser("roundzheng")) {
			userService.deleteUser("roundzheng");
        }
		System.out.println("roundzheng's password is \"" + userService.getPassword("roundzheng") + "\""+userService.readUser("roundzheng"));
		factory.destroySingletons();
		
    }

}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" 
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id="serviceTarget" class="test.spring.service.impl.UserServiceImpl" />
    <bean id="logAdvisor" class="test.spring.service.aop.LogAdvisor" />
    <bean id="service" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="proxyInterfaces"><value>test.spring.service.UserService</value></property>
        <property name="target"><ref local="serviceTarget"/></property>
        <property name="interceptorNames">
            <list>
                <value>logAdvisor</value>
            </list>
        </property>
    </bean>
</beans>